Example of weak entity, Database Management System

Consider the entity type dependent related to employee entity, which is used to keep track of the dependents of every employee. The attributes of dependents are: name, sex, birth date and relationship. Every employee entity is said to own the dependent entities that are related to it. Though, please note that the 'dependent' entity does not be of its own, it is dependent on the Employee entity. We can also say that in case an employee leaves the organisation all dependents related to him/her also leave along with. Therefore, the 'dependent' entity has no significance without the entity 'employee'. Therefore, it is a weak entity.

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